Kogan mini PC requires 12 V 2A DC Power. Can I connect it to a car battery? Or do I need a voltage regulator? If so, what is a suitable device?
You’d definitely need a regulator. A car’s electrical system will give you anywhere from 8V - 15V, depending on charge and current draw etc.
What exactly are you trying to do by powering it from a battery?
It is on a yacht. The computer is supplied with an 240 V adapter but If possible I want to avoid using a noisy, greedy inverter. The yacht system mostly runs around 14.4 V and powers lights, refrigeration, navigation gear etc but yes, it does vary. Jaycar have sold me a switchable gizmo for an auto appliance socket but it is clunky. I’d like to put something in line hard wired. Like this? 8-40V to 12V 6A DC Voltage Stabilizer 72W Car Power Supply Regulator A.U | eBay
Yep. The eBay link should work nicely. 8V to 40V input and 12VDC output with some capacity to spare if you only need 2A. Looks like it might be semi water proof too.